scholarly journals Gamma‐Ray Emission from the Broad‐Line Radio Galaxy 3C 111

2008 ◽  
Vol 688 (2) ◽  
pp. 852-858 ◽  
Author(s):  
R. C. Hartman ◽  
M. Kadler ◽  
J. Tueller
Keyword(s):  
Gamma Ray ◽  
Radio Galaxy ◽  
Broad Line ◽  
Gamma Ray Emission

scholarly journals X-ray and Gamma-ray Variability of NGC 1275

Galaxies ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 63
Author(s):  
Varsha Chitnis ◽  
Amit Shukla ◽  
K. P. Singh ◽  
Jayashree Roy ◽  
Sudip Bhattacharyya ◽  
...  
Keyword(s):  
Time Scales ◽  
Gamma Ray ◽  
Radio Galaxy ◽  
Cluster Emission ◽  
X Ray ◽  
Gamma Ray Emission ◽  
High Degree ◽  
Ngc 1275 ◽  
Perseus Cluster ◽  
Very High

Gamma-ray emission from the bright radio source 3C 84, associated with the Perseus cluster, is ascribed to the radio galaxy NGC 1275 residing at the centre of the cluster. Study of the correlated X-ray/gamma-ray emission from this active galaxy, and investigation of the possible disk-jet connection, are hampered because the X-ray emission, particularly in the soft X-ray band (2–10 keV), is overwhelmed by the cluster emission. Here we present a method to spectrally decouple the cluster and active galactic nucleus (AGN) emission in imaging X-ray detectors. We use three sets of simultaneous Niel Gehrels Swift XRT and NuStar data. These observations were made during the period 2015 November to 2017 February, when a huge increase in the gamma-ray emission was observed. We find that the gamma-ray emission shows a very high degree of variability (40%–50%) on time scales of 1–10 days, whereas the hard X-ray emission, associated with the AGN, shows a low variability (∼15%–30%), on various time scales in the range of 0.01–60 days.

scholarly journals THE CONNECTION BETWEEN THE RADIO JET AND THE GAMMA-RAY EMISSION IN THE RADIO GALAXY 3C 120

2015 ◽  
Vol 808 (2) ◽  
pp. 162 ◽  
Author(s):  
Carolina Casadio ◽  
José L. Gómez ◽  
Paola Grandi ◽  
Svetlana G. Jorstad ◽  
Alan P. Marscher ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Radio Galaxy ◽  
Gamma Ray Emission ◽  
3C 120

scholarly journals Broad-line type Ic SN 2020bvc

2020 ◽  
Vol 639 ◽  
pp. L11 ◽  
Author(s):  
L. Izzo ◽  
K. Auchettl ◽  
J. Hjorth ◽  
F. De Colle ◽  
C. Gall ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Optical Spectra ◽  
Gamma Ray Bursts ◽  
Archival Data ◽  
Broad Line ◽  
X Ray ◽  
Long Duration ◽  
Gamma Ray Emission ◽  
Very High ◽  
Line Type

Long-duration gamma-ray bursts (GRBs) are almost unequivocally associated with very energetic, broad-line supernovae of Type Ic-BL. While the gamma-ray emission is emitted in narrow jets, the SN emits radiation isotropically. Therefore, it has been hypothesized that some SN Ic-BL not associated with GRBs arise from events with inner engines such as off-axis GRBs or choked jets. Here we present observations of the nearby (d = 120 Mpc) SN 2020bvc (ASAS-SN 20bs) that support this scenario. Swift-UVOT observations reveal an early decline (up to two days after explosion), while optical spectra classify it as a SN Ic-BL with very high expansion velocities (≈70 000 km s−1), similar to that found for the jet-cocoon emission in SN 2017iuk associated with GRB 171205A. Moreover, the Swift X-Ray Telescope and CXO X-ray Observatory detected X-ray emission only three days after the SN and decaying onward, which can be ascribed to an afterglow component. Cocoon and X-ray emission are both signatures of jet-powered GRBs. In the case of SN 2020bvc, we find that the jet is off axis (by ≈23 degrees), as also indicated by the lack of early (≈1 day) X-ray emission, which explains why no coincident GRB was detected promptly or in archival data. These observations suggest that SN 2020bvc is the first orphan GRB detected through its associated SN emission.

scholarly journals ON THE GAMMA-RAY EMISSION FROM THE CORE AND RADIO LOBES OF THE RADIO GALAXY CENTAURUS A

2014 ◽  
Vol 28 ◽  
pp. 1460182
Author(s):  
NAREK SAHAKYAN ◽  
FRANK M. RIEGER ◽  
FELIX AHARONIAN ◽  
RUIZHI YANG ◽  
EMMA DE ONA-WILHELMI
Keyword(s):  
Power Law ◽  
Gamma Ray ◽  
Radio Galaxy ◽  
Spectral Energy Distribution ◽  
High Energy ◽  
Spectral Energy ◽  
Radio Image ◽  
The Core ◽  
Gamma Ray Emission ◽  
Centaurus A

We summarize recent results based on an analysis of Fermi-LAT data for the lobes and the core of the nearby radio galaxy Centaurus A (Cen A). In the case of the core, high-energy (HE; > 100 MeV) γ-rays up to 50 GeV have been detected with a detection significance of about 44σ. The average gamma-ray spectrum of the core reveals interesting evidence for a possible deviation from a simple power-law. A likelihood analysis with a broken power-law model shows that the photon index becomes substantially harder above Eb ≃ 4 GeV, changing from Γ1 = 2.74 ± 0.03 below to Γ2 = 2.09 ± 0.20 above. It seems possible that this hardening marks the contribution of an additional high-energy component beyond the common synchrotron-self Compton jet emission. In the case of the lobes, the high-energy gamma-ray emission extends up to 6 GeV, with a significance of more than 10 and 20 σ for the north and the south lobe, respectively. Based on a detailed spatial analysis and comparison with the associated radio lobes, a substantial extension of the HE γ-ray emission beyond the WMAP radio image for the northern lobe of Cen A is found. We provide a short discussion of the lobe's spectral energy distribution (SED) in the context of hadronic and time-dependent leptonic scenarios.

Gamma-ray emission in the radio galaxy NGC 5128

2013 ◽  
Vol 7 (6) ◽  
pp. 674-682
Author(s):  
Yu. P. Vagin ◽  
N. L. Stal’ ◽  
A. O. Nikitin ◽  
V. S. Chudnovsky ◽  
A. V. Rybakova
Keyword(s):  
Gamma Ray ◽  
Radio Galaxy ◽  
Gamma Ray Emission

scholarly journals FERMILARGE AREA TELESCOPE DETECTION OF EXTENDED GAMMA-RAY EMISSION FROM THE RADIO GALAXY FORNAX A

2016 ◽  
Vol 826 (1) ◽  
pp. 1 ◽  
Author(s):  
M. Ackermann ◽  
M. Ajello ◽  
L. Baldini ◽  
J. Ballet ◽  
G. Barbiellini ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Radio Galaxy ◽  
Gamma Ray Emission

Search for very high energy gamma-ray emission from the peculiar radio galaxy IC 310 with TACTIC during 2012 to 2015

New Astronomy ◽  
2018 ◽  
Vol 60 ◽  
pp. 42-47 ◽  
Author(s):  
B. Ghosal ◽  
K.K. Singh ◽  
K.K. Yadav ◽  
A.K. Tickoo ◽  
R.C. Rannot ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Radio Galaxy ◽  
High Energy ◽  
High Energy Gamma ◽  
Very High Energy ◽  
Energy Gamma ◽  
Gamma Ray Emission ◽  
Very High

External blob radiation model for the TeV gamma-ray emission in radio galaxies

2018 ◽  
Vol 14 (S342) ◽  
pp. 246-247
Author(s):  
Wlodek Bednarek ◽  
Piotr Banasiński
Keyword(s):  
Gamma Ray ◽  
Radio Galaxy ◽  
Large Angle ◽  
Radio Galaxies ◽  
Radiation Model ◽  
Gamma Ray Emission ◽  
Jet Axis ◽  
Soft Radiation

AbstractWe propose that two emission regions are present in the decelerating jet of radio galaxy at this same moment. Isotropic electrons, in the farther blob as counted along the jet, up-scatter mono-directional soft radiation, from the closer blob, at a relatively large angles to the jet axis. Such model can naturally explain the large angle gamma-ray emission observed from radio galaxies.

ASCAObservations of the Broad‐Line Radio Galaxy 3C 445

1998 ◽  
Vol 495 (2) ◽  
pp. 749-756 ◽  
Author(s):  
Rita M. Sambruna ◽  
I. M. George ◽  
R. F. Mushotzky ◽  
K. Nandra ◽  
T. J. Turner
Keyword(s):  
Radio Galaxy ◽  
Broad Line
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